An implicit timemarching method for studying unsteady flow with massive separation
Abstract
A fully implicit timemarching method is developed such that all spatial derivatives are approximated using central differences, but no use is made of any artificial dissipation. The numerical method solves the discretized equations using Alternating Direction ImplicitBlock Gaussian Elimination technique. The method is implemented in the unsteady analysis, which solves the incompressible NavierStokes equations in terms of vorticity and stream function in generalized orthogonal coordinates. A clustered conformal Cgrid is employed, and every effort is made to resolve the various length scales in the flow problem. The metric discontinuity at the branchcut is treated appropriately using analytic continuation. Introduction of the BGE reordering permits implicit treatment of the branch cut in the numerical method. The vorticity singularity at the cusped trailing edge is also appropriately treated. This accurate and efficient implicit method is used to study flow at Re = 1000, past a 12percent thick symmetric Joukowski airfoil at high angle of attack 30 and 53 deg.
 Publication:

7th Computational Fluid Dynamics Conference
 Pub Date:
 1985
 Bibcode:
 1985cfd..conf...25O
 Keywords:

 Computational Fluid Dynamics;
 NavierStokes Equation;
 Separated Flow;
 Time Marching;
 Unsteady Flow;
 Airfoils;
 Angle Of Attack;
 Boundary Value Problems;
 Gaussian Elimination;
 Numerical Flow Visualization;
 Stream Functions (Fluids);
 Viscous Flow;
 Vorticity Equations;
 Fluid Mechanics and Heat Transfer